This invention relates to a branching filter and to a transmitter-receiver which comprises a branching filter under consideration. A branching filter has a transmitter port for receiving an input transmit signal, a receiver port, and an antenna port for receiving an input receive signal and is for distributing the input transmit signal to the antenna port and the input receive signal to the receiver port.
A conventional branching filter comprises a transmit filter, a waveguide branching filter coupled to the transmit filter, a curved waveguide coupled to the waveguide branching filter, and a receive filter coupled to the curved waveguide. It is impossible to easily and cheaply produce the conventional branching filter. Inasmuch as the transmit filter is large, the conventional branching filter is large.
A transmitter-receiver comprises a transmitter module, a branching filter module coupled to the transmitter module, and a receiver module coupled to the branching filter module.
In a conventional transmitter-receiver, a transmitter module comprises a transmitter connector. A receiver module comprises a receiver connector. On putting the transmitter-receiver in operation, a cable is connected to the transmitter connector and the receiver connector. Points of connection of the cable to the transmitter connector and the receiver connector are covered for hermetic seal and for insuring waterproofness by a first and a second connector cover. It is hardly possible in the conventional transmitter-receiver to exchange the first and the second connector covers to a new cover.